Sodium citrate and caustic as process aids for the extraction of bitumen from mined oil sands

Abstract

A process for extracting bitumen from an oil sand ore having a fines content up to about 60% and a bitumen content higher than about 6% is provided, comprising mixing the oil sand ore with heated water to form an oil sand slurry; conditioning the oil sand slurry to form a conditioned oil sand slurry; introducing a dosage of sodium citrate to the process either prior to or during the mixing step, or prior to or during the conditioning step, or both; and introducing the conditioned oil sand slurry into a separation zone to form a bitumen froth and tailings.

What is claimed: 
     
       1. A process of extracting bitumen from oil sand ores, comprising:
 determining a dosage (wt %) of caustic necessary to maximize the bitumen recovery for the oil sand ore to be processed when using caustic alone as a processing aid; 
 determining an amount of caustic (wt %) and an amount of sodium citrate (wt %) which yields substantially the same bitumen recovery or greater as the dosage (wt %) of caustic alone; 
 mixing the oil sand ore with heated water to produce an oil sand slurry; and 
 adding the amounts of caustic (wt %) and sodium citrate (wt %) before, during or after mixing the oil sand ore with heated water to condition the oil sand slurry and to improve bitumen recovery from the oil sand ore; 
 wherein the sum of the amounts of caustic (wt %) and sodium citrate (wt %) is equal to or less than the dosage (wt %) of caustic alone. 
 
     
     
       2. The process of  claim 1 , wherein the bitumen content ranges from about 6% to about 10%, the fines content is greater than about 25%, the caustic amount ranges from about 0.01 wt % to about 0.05 wt %, and the sodium citrate amount ranges from about 0.003 wt % to about 0.05 wt %. 
     
     
       3. The process of  claim 2 , wherein the bitumen content is about 8%, the fines content is about 40%, the caustic amount is about 0.03 wt %, and the sodium citrate amount is about 0.015 wt %. 
     
     
       4. The process of  claim 2 , wherein the bitumen content is about 9%, the fines content is about 26%, the caustic amount is about 0.03 wt %, and the sodium citrate amount is about 0.05 wt %. 
     
     
       5. The process of  claim 2 , wherein the bitumen content is about 9.5%, the fines content is about 35%, the caustic amount is about 0.03 wt %, and the sodium citrate amount is about 0.04 wt %. 
     
     
       6. The process of  claim 1 , wherein the bitumen content is greater than about 10%, the fines content is less than about 20%, the caustic amount is about 0.01 wt %, and the sodium citrate amount ranges from about 0.003 wt % to about 0.03 wt %. 
     
     
       7. The process of  claim 6 , wherein the bitumen content is about 12%, the fines content is about 16%, the caustic amount is about 0.01 wt %, and the sodium citrate amount is about 0.02 wt %. 
     
     
       8. The process of  claim 1 , wherein a total dosage of caustic and sodium citrate is about 0.04 wt %, wherein the caustic amount ranges from about 0.01 wt % to about 0.03 wt %, and the sodium citrate amount ranges from about 0.01 wt % to about 0.03 wt %. 
     
     
       9. The process of  claim 1 , wherein the caustic comprises sodium hydroxide. 
     
     
       10. The process of  claim 1 , wherein the sodium citrate comprises trisodium citrate.